2005-04-16 16:20:36 -06:00
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# Makefile for the Linux device tree
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2012-01-22 14:31:15 -07:00
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obj-y := core.o bus.o dd.o syscore.o \
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2005-03-23 12:12:38 -07:00
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driver.o class.o platform.o \
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2007-05-06 15:49:09 -06:00
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cpu.o firmware.o init.o map.o devres.o \
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2011-11-24 00:04:39 -07:00
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attribute_container.o transport_class.o \
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topology.o
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Driver Core: devtmpfs - kernel-maintained tmpfs-based /dev
Devtmpfs lets the kernel create a tmpfs instance called devtmpfs
very early at kernel initialization, before any driver-core device
is registered. Every device with a major/minor will provide a
device node in devtmpfs.
Devtmpfs can be changed and altered by userspace at any time,
and in any way needed - just like today's udev-mounted tmpfs.
Unmodified udev versions will run just fine on top of it, and will
recognize an already existing kernel-created device node and use it.
The default node permissions are root:root 0600. Proper permissions
and user/group ownership, meaningful symlinks, all other policy still
needs to be applied by userspace.
If a node is created by devtmps, devtmpfs will remove the device node
when the device goes away. If the device node was created by
userspace, or the devtmpfs created node was replaced by userspace, it
will no longer be removed by devtmpfs.
If it is requested to auto-mount it, it makes init=/bin/sh work
without any further userspace support. /dev will be fully populated
and dynamic, and always reflect the current device state of the kernel.
With the commonly used dynamic device numbers, it solves the problem
where static devices nodes may point to the wrong devices.
It is intended to make the initial bootup logic simpler and more robust,
by de-coupling the creation of the inital environment, to reliably run
userspace processes, from a complex userspace bootstrap logic to provide
a working /dev.
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jan Blunck <jblunck@suse.de>
Tested-By: Harald Hoyer <harald@redhat.com>
Tested-By: Scott James Remnant <scott@ubuntu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-04-30 07:23:42 -06:00
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obj-$(CONFIG_DEVTMPFS) += devtmpfs.o
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2013-07-01 23:45:15 -06:00
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obj-$(CONFIG_DMA_CMA) += dma-contiguous.o
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2005-04-16 16:20:36 -06:00
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obj-y += power/
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2007-12-03 09:57:48 -07:00
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obj-$(CONFIG_HAS_DMA) += dma-mapping.o
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2009-07-12 07:44:55 -06:00
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obj-$(CONFIG_HAVE_GENERIC_DMA_COHERENT) += dma-coherent.o
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2013-06-27 05:48:16 -06:00
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obj-$(CONFIG_DMA_SHARED_BUFFER) += dma-buf.o reservation.o
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[PATCH] Driver model: add ISA bus
During the recent "isa drivers using platform devices" discussion it was
pointed out that (ALSA) ISA drivers ran into the problem of not having
the option to fail driver load (device registration rather) upon not
finding their hardware due to a probe() error not being passed up
through the driver model. In the course of that, I suggested a seperate
ISA bus might be best; Russell King agreed and suggested this bus could
use the .match() method for the actual device discovery.
The attached does this. For this old non (generically) discoverable ISA
hardware only the driver itself can do discovery so as a difference with
the platform_bus, this isa_bus also distributes match() up to the driver.
As another difference: these devices only exist in the driver model due
to the driver creating them because it might want to drive them, meaning
that all device creation has been made internal as well.
The usage model this provides is nice, and has been acked from the ALSA
side by Takashi Iwai and Jaroslav Kysela. The ALSA driver module_init's
now (for oldisa-only drivers) become:
static int __init alsa_card_foo_init(void)
{
return isa_register_driver(&snd_foo_isa_driver, SNDRV_CARDS);
}
static void __exit alsa_card_foo_exit(void)
{
isa_unregister_driver(&snd_foo_isa_driver);
}
Quite like the other bus models therefore. This removes a lot of
duplicated init code from the ALSA ISA drivers.
The passed in isa_driver struct is the regular driver struct embedding a
struct device_driver, the normal probe/remove/shutdown/suspend/resume
callbacks, and as indicated that .match callback.
The "SNDRV_CARDS" you see being passed in is a "unsigned int ndev"
parameter, indicating how many devices to create and call our methods with.
The platform_driver callbacks are called with a platform_device param;
the isa_driver callbacks are being called with a "struct device *dev,
unsigned int id" pair directly -- with the device creation completely
internal to the bus it's much cleaner to not leak isa_dev's by passing
them in at all. The id is the only thing we ever want other then the
struct device * anyways, and it makes for nicer code in the callbacks as
well.
With this additional .match() callback ISA drivers have all options. If
ALSA would want to keep the old non-load behaviour, it could stick all
of the old .probe in .match, which would only keep them registered after
everything was found to be present and accounted for. If it wanted the
behaviour of always loading as it inadvertently did for a bit after the
changeover to platform devices, it could just not provide a .match() and
do everything in .probe() as before.
If it, as Takashi Iwai already suggested earlier as a way of following
the model from saner buses more closely, wants to load when a later bind
could conceivably succeed, it could use .match() for the prerequisites
(such as checking the user wants the card enabled and that port/irq/dma
values have been passed in) and .probe() for everything else. This is
the nicest model.
To the code...
This exports only two functions; isa_{,un}register_driver().
isa_register_driver() register's the struct device_driver, and then
loops over the passed in ndev creating devices and registering them.
This causes the bus match method to be called for them, which is:
int isa_bus_match(struct device *dev, struct device_driver *driver)
{
struct isa_driver *isa_driver = to_isa_driver(driver);
if (dev->platform_data == isa_driver) {
if (!isa_driver->match ||
isa_driver->match(dev, to_isa_dev(dev)->id))
return 1;
dev->platform_data = NULL;
}
return 0;
}
The first thing this does is check if this device is in fact one of this
driver's devices by seeing if the device's platform_data pointer is set
to this driver. Platform devices compare strings, but we don't need to
do that with everything being internal, so isa_register_driver() abuses
dev->platform_data as a isa_driver pointer which we can then check here.
I believe platform_data is available for this, but if rather not, moving
the isa_driver pointer to the private struct isa_dev is ofcourse fine as
well.
Then, if the the driver did not provide a .match, it matches. If it did,
the driver match() method is called to determine a match.
If it did _not_ match, dev->platform_data is reset to indicate this to
isa_register_driver which can then unregister the device again.
If during all this, there's any error, or no devices matched at all
everything is backed out again and the error, or -ENODEV, is returned.
isa_unregister_driver() just unregisters the matched devices and the
driver itself.
More global points/questions...
- I'm introducing include/linux/isa.h. It was available but is ofcourse
a somewhat generic name. Moving more isa stuff over to it in time is
ofcourse fine, so can I have it please? :)
- I'm using device_initcall() and added the isa.o (dependent on
CONFIG_ISA) after the base driver model things in the Makefile. Will
this do, or I really need to stick it in drivers/base/init.c, inside
#ifdef CONFIG_ISA? It's working fine.
Lastly -- I also looked, a bit, into integrating with PnP. "Old ISA"
could be another pnp_protocol, but this does not seem to be a good
match, largely due to the same reason platform_devices weren't -- the
devices do not have a life of their own outside the driver, meaning the
pnp_protocol {get,set}_resources callbacks would need to callback into
driver -- which again means you first need to _have_ that driver. Even
if there's clean way around that, you only end up inventing fake but
valid-form PnP IDs and generally catering to the PnP layer without any
practical advantages over this very simple isa_bus. The thing I also
suggested earlier about the user echoing values into /sys to set up the
hardware from userspace first is... well, cute, but a horrible idea from
a user standpoint.
Comments ofcourse appreciated. Hope it's okay. As said, the usage model
is nice at least.
Signed-off-by: Rene Herman <rene.herman@keyaccess.nl>
2006-06-06 15:54:02 -06:00
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obj-$(CONFIG_ISA) += isa.o
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2005-04-16 16:20:36 -06:00
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obj-$(CONFIG_FW_LOADER) += firmware_class.o
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obj-$(CONFIG_NUMA) += node.o
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2006-10-01 00:27:08 -06:00
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obj-$(CONFIG_MEMORY_HOTPLUG_SPARSE) += memory.o
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2007-12-31 11:05:43 -07:00
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ifeq ($(CONFIG_SYSFS),y)
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2007-11-28 13:23:18 -07:00
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obj-$(CONFIG_MODULES) += module.o
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2007-12-31 11:05:43 -07:00
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endif
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2006-05-09 04:53:49 -06:00
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obj-$(CONFIG_SYS_HYPERVISOR) += hypervisor.o
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2011-05-11 11:59:58 -06:00
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obj-$(CONFIG_REGMAP) += regmap/
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2012-02-06 12:22:22 -07:00
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obj-$(CONFIG_SOC_BUS) += soc.o
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drivers/pinctrl: grab default handles from device core
This makes the device core auto-grab the pinctrl handle and set
the "default" (PINCTRL_STATE_DEFAULT) state for every device
that is present in the device model right before probe. This will
account for the lion's share of embedded silicon devcies.
A modification of the semantics for pinctrl_get() is also done:
previously if the pinctrl handle for a certain device was already
taken, the pinctrl core would return an error. Now, since the
core may have already default-grabbed the handle and set its
state to "default", if the handle was already taken, this will
be disregarded and the located, previously instanitated handle
will be returned to the caller.
This way all code in drivers explicitly requesting their pinctrl
handlers will still be functional, and drivers that want to
explicitly retrieve and switch their handles can still do that.
But if the desired functionality is just boilerplate of this
type in the probe() function:
struct pinctrl *p;
p = devm_pinctrl_get_select_default(&dev);
if (IS_ERR(p)) {
if (PTR_ERR(p) == -EPROBE_DEFER)
return -EPROBE_DEFER;
dev_warn(&dev, "no pinctrl handle\n");
}
The discussion began with the addition of such boilerplate
to the omap4 keypad driver:
http://marc.info/?l=linux-input&m=135091157719300&w=2
A previous approach using notifiers was discussed:
http://marc.info/?l=linux-kernel&m=135263661110528&w=2
This failed because it could not handle deferred probes.
This patch alone does not solve the entire dilemma faced:
whether code should be distributed into the drivers or
if it should be centralized to e.g. a PM domain. But it
solves the immediate issue of the addition of boilerplate
to a lot of drivers that just want to grab the default
state. As mentioned, they can later explicitly retrieve
the handle and set different states, and this could as
well be done by e.g. PM domains as it is only related
to a certain struct device * pointer.
ChangeLog v4->v5 (Stephen):
- Simplified the devicecore grab code.
- Deleted a piece of documentation recommending that pins
be mapped to a device rather than hogged.
ChangeLog v3->v4 (Linus):
- Drop overzealous NULL checks.
- Move kref initialization to pinctrl_create().
- Seeking Tested-by from Stephen Warren so we do not disturb
the Tegra platform.
- Seeking ACK on this from Greg (and others who like it) so I
can merge it through the pinctrl subsystem.
ChangeLog v2->v3 (Linus):
- Abstain from using IS_ERR_OR_NULL() in the driver core,
Russell recently sent a patch to remove it. Handle the
NULL case explicitly even though it's a bogus case.
- Make sure we handle probe deferral correctly in the device
core file. devm_kfree() the container on error so we don't
waste memory for devices without pinctrl handles.
- Introduce reference counting into the pinctrl core using
<linux/kref.h> so that we don't release pinctrl handles
that have been obtained for two or more places.
ChangeLog v1->v2 (Linus):
- Only store a pointer in the device struct, and only allocate
this if it's really used by the device.
Cc: Felipe Balbi <balbi@ti.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Mitch Bradley <wmb@firmworks.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: Rickard Andersson <rickard.andersson@stericsson.com>
Cc: Russell King <linux@arm.linux.org.uk>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
[swarren: fixed and simplified error-handling in pinctrl_bind_pins(), to
correctly handle deferred probe. Removed admonition from docs not to use
pinctrl hogs for devices]
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2013-01-22 10:56:14 -07:00
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obj-$(CONFIG_PINCTRL) += pinctrl.o
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2005-04-16 16:20:36 -06:00
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2010-09-24 13:17:11 -06:00
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ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG
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2005-04-16 16:20:36 -06:00
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